Experimental Physics and
Industrial Control System

$ caget lbc:side0:dewarTemp.UDF
lbc:side0:dewarTemp.UDF        0

$ caput lbc:side0:dewarTemp.UDF 1
Old : lbc:side0:dewarTemp.UDF        0
New : lbc:side0:dewarTemp.UDF        0

record(ao, "lbc:side0:dewarTemp")
{
        field(DESC, "LBC Blue temperature")
        field(EGU, "degrees K")
        field(HIHI, "215")
        field(HIGH, "210")
        field(LOW, "165")
        field(LOLO, "160")
        field(HHSV, "MAJOR")
        field(HSV, "MINOR")
        field(LSV, "MINOR")
        field(LLSV, "MAJOR")
}

Hi Kellee,

   I did something like what you are doing. The PV values are written to by a bash script.
If/when the source data did not exist or was stale I did I wrote 1 to the record's UDF field
which set it invalid.

      # Set undefined.
      #
      caput ${pvname:?}.UDF  1  


where worked for me, i.e. set SEVR to INVALID and STAT to UDF (using base-3.14.12.3)
Regards

Andrew C. Starritt | Principal Controls Engineer | Australian Synchrotron 
p: (03) 8540 4164 | f: (03) 8540 4200
[email protected] | www.synchrotron.org.au
800 Blackburn Road, Clayton, Victoria 3168

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Kellee Summers
Sent: Thursday, 14 August 2014 12:50 AM
To: Lionberger, Carl A.; [email protected]
Subject: Re: How to tag soft channels as undefined/disconnected

This sounds pretty simple and what I'm trying to do.  The problem is I 
don't know how to do this part:  "sets the PV invalid"
How do you do that?  Is that just some kind of timeout on the processing?

Thanks for your help,
Kellee

On 08/13/2014 06:47 AM, Lionberger, Carl A. wrote:

For a project where I had a python program updating soft PVs, I wrote a timeout device support to use instead of the soft channel device support.  It times out and sets the PV invalid if a new value was not put to it within the timeout period since the last put. The C++ application just wouldn't put the value to the PV if the instrument data was invalid, and then the PV would go invalid without further action.  When valid data became available, the application would put it to the PV and the PV status would go normal again.

Carl

Carl Lionberger
Instrument Data Acquisition and Controls
Spallation Neutron Source
________________________________________
From: [email protected] <[email protected]> on behalf of Kellee Summers <[email protected]>
Sent: Tuesday, August 12, 2014 7:02 PM
To: [email protected]
Subject: How to tag soft channels as undefined/disconnected

Hi All,

We have set up an EPICS R3.14.12.4 database of pure software channels
(on a Linux system) so that we can use the alarm handler. The channel
values are being driven by a C++ software application that reads our
instrument data.   When the instrument data is stale (determined by an
out-of-date timestamp), I would like to
set the channels to UDF so that the alarm state is INVALID.

The SEVR and STAT alarm fields are non-modifiable.  I tried setting the
UDF field but it didn't give me a disconnected channel.

Do I need to modify the record processing?

Suggestions?

Thanks